From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755406AbdIGPbE (ORCPT ); Thu, 7 Sep 2017 11:31:04 -0400 Received: from mail-pg0-f53.google.com ([74.125.83.53]:33456 "EHLO mail-pg0-f53.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753973AbdIGPbB (ORCPT ); Thu, 7 Sep 2017 11:31:01 -0400 X-Google-Smtp-Source: ADKCNb6nRQO2i8ocVyO9w6nk+UkV5p5Io0NrpXQcHekeabRmdvjeRZ0iHhYbICZbAKAXU64pZAIQMQ== From: Kees Cook To: Ingo Molnar Cc: Kees Cook , Thomas Garnier , Thomas Gleixner , Russell King , Catalin Marinas , Will Deacon , Andy Lutomirski , Will Drewry , Al Viro , Dave Martin , Pratyush Anand , Dave Hansen , Arnd Bergmann , David Howells , Yonghong Song , linux-arm-kernel@lists.infradead.org, linux-api@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 4/4] arm64/syscalls: Move address limit check in loop Date: Thu, 7 Sep 2017 08:30:47 -0700 Message-Id: <1504798247-48833-5-git-send-email-keescook@chromium.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1504798247-48833-1-git-send-email-keescook@chromium.org> References: <1504798247-48833-1-git-send-email-keescook@chromium.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Thomas Garnier A bug was reported on ARM where set_fs might be called after it was checked on the work pending function. ARM64 is not affected by this bug but has a similar construct. In order to avoid any similar problems in the future, the addr_limit_user_check function is moved at the beginning of the loop. Fixes: cf7de27ab351 ("arm64/syscalls: Check address limit on user-mode return") Reported-by: Leonard Crestez Signed-off-by: Thomas Garnier Signed-off-by: Kees Cook --- arch/arm64/kernel/signal.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c index c45214f8fb54..0bdc96c61bc0 100644 --- a/arch/arm64/kernel/signal.c +++ b/arch/arm64/kernel/signal.c @@ -751,10 +751,10 @@ asmlinkage void do_notify_resume(struct pt_regs *regs, */ trace_hardirqs_off(); - /* Check valid user FS if needed */ - addr_limit_user_check(); - do { + /* Check valid user FS if needed */ + addr_limit_user_check(); + if (thread_flags & _TIF_NEED_RESCHED) { schedule(); } else { -- 2.7.4